People come for the rewards and stay after trying it. It's how many sites, including crypto faucets work. Especially given how difficult it seems to be able to get anywhere on here.
Remember that people are being asked to create something for the benefit of the community, and yes themselves, but if they don't see a way of earning from this they may decide it's too much work for nothing.
I expect a number of people are on cashback sites, I'm on a British one where you get the usual financial rewards (cashback) but also shares in a UK based PLC. May not get rich but it's something that ties all of us members to that website/community and the company.
Trying to earn online means there will be people that create content and think Steemit is going to be like Helium years ago, where we wrote articles and received a share of the income. But they also want it to be fair and to be rewarded for actually joining up and participating. Years ago we'd have been given free shares in the companies running websites, that doesn't happen much now, but this is the network economy and giving to others to encourage their continued participation would strengthen the network. And maybe in the future, they'll be the ones buying up all of the Steem and keeping everything funded...